The application's goal is to define better the pathogenesis of violence in psychiatric inpatients by taking into consideration both dispositional (person) and environmental variables. On the basis of the literature and pilot studies, we are suggesting that impatient violence is a heterogeneous phenomenon, i.e. that dispositional and environmental factors play a different role and interact in a dissimilar fashion depending on the type of violence. Trait violence (type I), a more chronic form, can be differentiated from state violence (type II), a more limited type. There are also patients with no dispositional tendencies (state or trait) to violence who may be violent on rare occasions because of an unfavorable environment (type 0). This typology takes into consideration both frequency of violence and degree to which the environment is conducive to violence. Pilot studies indicated that within a fixed and favorable environment, patients with more episodes of violence could be differentiated from those with few episodes on various dispositional characteristics. The specific aims are: to extend the findings of the pilot studies by considering a broad range of environmental conditions and a) contrast type I, type II and type 0 patients on psychiatric symptomatology, neurological/neuropsychological impairment and social functioning b) study the effect of the environment which is hypothesized to be different in the various groups. In addition we will define better the specific pattern of the neurological impairment and its etiology in the type I patients. Psychiatric inpatients will be drawn from 2 sites, Rockland Psychiatric Center and Manhattan Psychiatric Center. All patients with one assaultive incident and their non violent controls will be followed for one month; during this period all violent incidents will be carefully monitored and recorded; the ward environment will be evaluated. Approximately 1,000 patients will be followed in this fashion. The data obtained will be used to classify patients on the basis of frequency of violence and environmental risk factors. Out of this group, 240 patients (80 type I patients matched to 80 type II and to 80 type 0) will receive a complete evaluation consisting of a historical and demographic interview, a quantified neurological examination, a comprehensive neuropsychological evaluation, BPRS, CGI, and social dysfunction scales. Data analysis will permit examination of the hypotheses.